A bit of background: Novartis and the DHHS partnered to build the plant, with the idea that the cell-based method would be an important step forward from the traditional egg-based method.

There are a couple of reasons for that. One is that the cell-culture method (using Madin-Darby Canine Kidney, or MDCK cells) is more flexible; some avian flu strains, for which we might someday want a vaccine, are fatal to chickens in embryo.

The dog cells, on the other hand, can handle those just fine.

Also, the rate-limiting factor in the egg-based method is -- you guessed it -- eggs. As matters stand, there are usually enough eggs to produce the 135 million-odd doses used in the U.S. every year.

But if there's a plague among the chickens, production can run into problems.

Equally, if there's a sudden demand for a novel flu vaccine -- if a pandemic strain erupts, for instance -- all the available eggs might already be incubating the seasonal vaccine.

That wouldn't be fatal -- chickens lay a lot of eggs, after all -- but it could delay matters.

The Holly Springs plant will make Novartis' trivalent Flucelvax, starting next year. Flucelvax made in Europe was used last year after the FDA approved it as the first cell-culture flu vaccine in the U.S.

Generally, I have to regard this a step in the right direction. Power is best defined as the ability to keep options open; inasmuch as the new(ish) technology gives us more options, it's a powerful tool.

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